Google
Google has grown from a PhD thesis of two Stanford University students into a multi billion dollar goliath, which has single-handedly transformed the Internet and how other online businesses run their operations.
Google is by far the most popular search destination, and in turn the most desirable place for companies to hold good ranking positions (top 10). Google is arguably the toughest engine to rank in, as the algorithm is more sophisticated than other engines, and picks apart every minutia of a website.
You can find out more about Google through the following links:
http://www.google.com/intl/en/about.html
http://www.google.com/support/webmasters/bin/answer.py?answer=35291
http://www.google.com/support/webmasters/bin/answer.py?answer=35769
